Formosa Plastics HDPE TAISOX 7001 is a high-density polyethylene resin supplied for injection-moulding operations. The grade is characterized by a nominal melt flow rate of 20 g/10 min at 190°C under 2.16 kg load when tested in accordance with ASTM D1238 / ISO 1133-1. Nominal density is 0.954 g/cm³ at 23°C per ASTM D1505 / ISO 1183-1. These two values place the material in the high-flow injection moulding segment of the high-density polyethylene range. In production-scale trial activity, the resin is directed toward short-cycle, thin-wall components where rapid cavity filling and part ejection are process-economy drivers. The material is supplied in pellet form and is typically processed on reciprocating-screw injection moulding machines with shot capacities matched to the finished article mass plus a cushion of 10–15% of barrel capacity. No predrying is mandated for most indoor storage conditions; however, at relative humidity above 60%, surface splay has been observed on vented barrels and can be controlled by tray drying at 75–80°C for 1–2 h.

What Distinguishes TAISOX 7001 from Lower-Melt-Flow HDPE Grades?

Comparison against lower-melt-flow injection HDPE grades is best expressed through the melt flow rate rather than through melt viscosity, because the melt flow rate is a single-point inverse-flow parameter under fixed shear stress. The nominal 20 g/10 min MFR of TAISOX 7001 places it approximately five to ten times higher than conventional general-purpose HDPE injection grades with melt flow rates in the 2–4 g/10 min range. This disparity corresponds to lower pressure drop across elongated flow paths and permits reduced wall thickness in ribbed parts. The trade-off appears in melt strength, which is not captured by MFR. TAISOX 7001 is not intended for extrusion blow moulding or film extrusion because parison and bubble stability are insufficient. In applications where environmental stress crack resistance is controlling, lower-melt-flow high-molecular-weight HDPE grades must be evaluated against ASTM D1693 or ASTM D256 data.

Capillary rheometry at 190°C can provide a more complete shear-viscosity curve than the single-point melt flow value. For high-flow HDPE of this density, the shear-thinning slope across shear rates from 100 s⁻¹ to 1000 s⁻¹ is steeper than that of a fractional-melt HDPE grade. That behavior is relevant in thin-wall tooling because the apparent viscosity in the cavity can be lower than suggested by the MFR alone. However, the same narrow molecular weight distribution that supports high flow can reduce die swell and melt elasticity, which is why the grade is not interchangeable with blow-moulding resin.

Formosa Plastics published nominal property data for TAISOX 7001 are organized below; values are not specification limits and must be confirmed against the applicable certificate of analysis.

The tensile yield and flexural modulus place the material in the intermediate stiffness band for high-density polyethylene injection grades. Elongation at break of 15% is lower than higher-molecular-weight HDPE grades, indicating thin-wall ductility is present but should not be extended to large cold-drawing operations. Izod notched impact of 5.0 kJ/m² is measured on injection-moulded notched specimens and is not transferable to unnotched, aged, or welded components. Shore D hardness of 66 is typical for HDPE of this density and should not be used as a scratch-resistance predictor.

When Thin-Wall Injection Moulding Demands a Melt Flow Rate Above 15 g/10 min

Barrel temperature profiles commonly range from 180°C at the feed throat to 210°C at the nozzle, with reverse profiles permitted on machines that maintain screw recovery below the cooling timer. A mould temperature of 20–35°C is maintained for dimensional control; lower mould temperatures shorten cooling time but may increase frozen-in stress and warpage in rectangular containers. Back pressure is limited to 0.5–1.5 MPa to avoid excessive shear heating, and screw surface speeds are held below 100 m/min unless a high-speed accumulator requires faster recovery with documented melt-temperature stability.

Injection pressures for thin-wall parts with flow-length-to-wall-thickness ratios above 120:1 can require 80–120 MPa at the injection cylinder; actual values must be derived from cavity pressure transducers rather than machine hydraulic gauges. For hot-runner tools, externally heated manifolds with full round internal profiles are preferred; cold-runner tools require full round runners of 4–8 mm diameter where part mass permits. Gate land lengths below 0.8 mm can freeze rapidly and reduce cycle time, but gate blush can occur if injection speed is not profiled. Clamp force selection follows projected area; a starting clamp force factor of 3–5 kN/cm² of projected area is used for HDPE parts, with thin-wall high packing pressure geometry potentially requiring 5–7 kN/cm².

Shrinkage measured after 24 h post-mould conditioning per ASTM D955 can be expected in the 1.5–2.5% range; shrinkage anisotropy between flow and cross-flow directions is usually less than 0.4% for thin-wall HDPE but must be verified for each geometry. Post-mould warpage in large flat parts is minimized by symmetric cooling and by holding gate-seal pressure until gate freeze-off; premature hold-pressure release produces sink marks and dimensional drift.

Applications for TAISOX 7001 are concentrated in high-cavitation, thin-wall packaging and consumer goods. Typical article types include margarine tubs, dairy spread containers, ice cream tubs, over-caps for aerosol cans, pails up to 5 L, crates, toys, and housewares. On high-speed injection lines with accumulator-assisted machines and multi-cavity hot-runner stack moulds, melt distribution is governed by manifold balance and valve-gate timing; published data for this specific configuration is limited, and cycle time must be established by tool trials. Gate size and location are more significant than barrel temperature for sink mark control in ribbed sections. In flat thin lids, sequential valve gating reduces weld-line visibility, but moving pins require increased maintenance intervals. The absence of mould release contamination is critical for food-contact lids; mould release should be omitted or qualified under the end-use migration protocol.

The Derating of Impact Performance in High-Melt-Flow HDPE Is Not Linear

High melt flow rate in HDPE is generally associated with lower molecular weight and reduced chain entanglement, which reduces notched Izod impact and environmental stress crack resistance. For TAISOX 7001, the published notched Izod impact of 5.0 kJ/m² is sufficient for many thin-wall containers but is not the controlling parameter for long-term load-bearing crates exposed to surfactants. Environmental stress crack resistance testing per ASTM D1693 is mandatory when the finished article will contact aggressive liquid media such as household cleaners, mould-release agents, or aliphatic hydrocarbons. The brittle-ductile transition is rate-dependent; high-speed dart impact testing per ASTM D1709 or instrumented puncture testing may reveal toughness differences that the notched Izod test does not capture.

Low-temperature impact should be evaluated by batch-specific falling-weight testing; published data for the -20°C condition for this specific grade is limited. The practical operating boundary is therefore application-dependent, and frozen food packaging should be tested for stack-drop behavior at the intended distribution temperature.

Compliance Tracking and End-Use Migration Limits

Compliance claims for TAISOX 7001 follow the regulatory status of high-density polyethylene homopolymers and copolymers. For food-contact use in the United States, the resin may be used as a component of articles intended for contact with food only when the fabricated article meets the extraction limitations of 21 CFR 177.1520 for olefin polymers. European Union compliance requires determination of overall migration and specific migration from the final article under Regulation (EU) No 10/2011; the overall migration limit of 10 mg/dm² applies unless individual component migration is more restrictive. REACH obligations are defined in Regulation (EC) No 1907/2006; ongoing SVHC declarations must be obtained from the supplier. For electrical and electronic applications, RoHS assessment under Directive 2011/65/EU Annex II is performed on the finished component, not on the unfilled polymer. Certifications should be requested as a letter of assurance from Formosa Plastics for the purchased lot.

TAISOX 7001 contains a process stabilizer system intended to protect melt viscosity during high-temperature compounding and injection moulding. Oxidative induction time testing per ASTM D3895 can be used as an incoming-lot screening tool; published data for this specific TAISOX lot is limited, so acceptance criteria should be set by the moulder’s quality protocol. The resin is not hygroscopic under normal storage; bulk silos should be purged with dry air if condensation risk exists. Blending with post-consumer recyclate is generally restricted to non-food applications. Many HDPE injection moulders validate up to 20 wt% of clean, unpigmented high-density polyethylene recyclate for non-food crates and pails; the appropriate level for TAISOX 7001 must be established by mechanical property retention trials because tensile yield and Izod impact retention are nonlinear with recyclate content. Pigment masterbatches with PE carriers are normally added at 2–4 wt%; inorganic pigments may nucleate crystallization and alter shrinkage by 0.1–0.3%. Avoid storage adjacent to polyvinyl chloride or polyvinylidene chloride waste because halogen-acid off-gassing accelerates embrittlement of high-density polyethylene during melt processing.